The present invention relates to a semiconductor integrated circuit with a built-in power supply circuit for stepping down the voltage of an external power supply; and a semiconductor integrated circuit device. For example, this invention relates to a technique suitable for use in storage systems having disk array apparatuses that require low-voltage and low-power semiconductor chips.
In accordance with the trend toward low operating voltages in semiconductor chips with logic circuits (internal logic), e.g., large scale integrated circuit (LSI) chips, semiconductor chips (LSI chips) with built-in power supply circuits such as DC-DC converters have been known. With the power supply circuits included in the semiconductor chips, the lengths of lines connecting the power supply circuits and the logic circuits may be short, thereby decreasing noise in the power supplies. In this case, if the built-in power supply circuits generate the power supply voltage used in the logic circuits, only one kind of power is supplied to the logic circuits, which facilitates substrate mounting.
However, in accordance with the trend toward multi supply voltages in semiconductor chips, if the semiconductor chips include both built-in 2.5V-power supply circuits and 1.5V-power supply circuits for stepping down the external 3.3 V power supply voltage to 2.5 V or 1.5 V, the sizes of the semiconductor chips will increase. Thereupon, for a semiconductor chip with multiplex power supplies, where a power supply circuit is composed of switching regulators, Japanese Patent Laid-Open Publication No. 2002-83872 proposes a semiconductor chip that has, from among a plurality of switching regulators, only control circuits driven by an external power supply mounted thereon, and adopts a configuration where MOS transistors etc. occupying large areas in the semiconductor chip are provided as external components.